         <div class="messge">
                <div class="messge_nav">聯繫我們</div>
                <div class="message_content">
                  <form action="{:U('Index/update')}" method="post" id="form_message">
                      <input type='hidden' name='title' value='留言板' id='post_title'>
                      <input type='hidden' name='category_id' value='48'>
                        <input type='hidden' name='model_id' value='10'>
                          <input type='hidden' name='type' value='2'>
                          <input type='hidden' name='description' value=''>
                    <input class="message_input " type="text" name="names" id='post_name' onfocus="if (value == '姓名') {
                          value = ''
                      }" onblur="if (value == '') {
                                  value = '姓名'
                              }" value="姓名" />
                    <input class="message_input" type="text" name="tel" onfocus="if (value == '電話') {
                                          value = ''
                                      }" onblur="if (value == '') {
                                                  value = '電話'
                                              }" value="電話" />
                    <input class="message_input" type="text" name="emails" onfocus="if (value == '郵箱') {
                                                          value = ''
                                                      }" onblur="if (value == '') {
                                                                  value = '郵箱'
                                                              }" value="郵箱" />
                    <textarea class="message_text_area" name="content"></textarea>
                    <input class="message_button" type="submit" value="發送" />
                  </form>
                </div>
              </div>
<script>
window.onload = function(){
    var name = document.getElementById('post_name');
    var title = document.getElementById('post_title');
    name.onblur = function(){
       title.value = "來自"+name.value+"的留言";
    }
}
</script>